This group of studies examines how dysmorphism in the cerebellum and midbrain is related to behavioral dysfunction in children with spina bifida meningomyelocele and hydrocephalus (SBH). SBH is associated with defining dysmorphologies of the cerebellum and midbrain, as well as with characteristic cognitive deficits in coordinate movement (movements are erratic and poorly timed), visuo-spatial analysis (difficult with visual attention, spatial visualization, and spatial orientation), and automatization. Although SBH disrupts both brain structure and cognitive function, the prototypical dysmorphisms of the cerebellum and midbrain have not been quantified; the signature functional deficits in coordinate movement, visuo-spatial analysis and automatization have been measured but not analyzed with respect to core processes; and the relations between dysmorphology and dysfunction have not been explained. We have three specific aims: AIM1 is to measure brain dysmorphism in both volume and shape in the cerebellum and midbrain. AIM2 is to describe dysfunction for: clinical markers (signs of dysfunction in the cerebellum and midbrain), signature psychometric test deficits in coordinate movement, visuo-spatial analysis, and automatization, and core processed deemed on the basis of cognitive theory to underlie each signature test deficit. AIM 3 is to examine correlations between functional outcome and MRI indices of brain dysmorphism. These aims will be pursued in a sample of 335 children with SBH and 96 controls, all 8-15 years of age. The large sample and the proposed analysis of brain structure-cognitive function relations should provide a unique window into the source of variability in motor and attention deficits in children with SBH in relation to their prototypical cerebellum and midbrain dysmorphologies.